Passenger vehicles for roadways, such as cars, trucks, or other automobiles, typically include doors whose ends are configured to transfer loading, such as standard dynamic and quasi-static loading during test procedures under Federal Motor Vehicle Safety Standards (FMVSS) 214, to static structures of a body structure of the passenger vehicle. In four-door vehicles (i.e., those having two openable doors on each side of a vehicle to provide passenger ingress and egress), the body structure of the vehicle typically includes an intermediately positioned vertical structure (e.g., a “B-pillar”) extending upward from a floor structure to a roof structure of the body, which transfers standard loading from a rear end of a front door and a front end of a rear door to the roof and floor structures of the vehicle body. Other vehicles may include a movable vertical structure (e.g., contained in a front end of the rear door), which similarly transfers standard loading from the rear end of the front door and the front end of the rear door to the vehicle body. These vertical structures, however, impede passengers' view from inside to outside the vehicle, and can also define separate openings for passenger ingress/egress.